In the past, semiconductor wafers were processed through various processing stages or steps depending usually upon which semiconductor devices were being fabricated in the semiconductor chips that all together comprised the semiconductor wafers. For example, bipolar semiconductor devices usually had a series of processing steps that were different, at least in some respects, to the processing steps used to fabricate MOS or unipolar semiconductor devices. Consequently, semiconductor chips that were fabricated in a single wafer that contained bipolar semiconductor devices could have dimensions different than semiconductor chips, for example, that contained MOS or CMOS devices. Furthermore, a single wafer fabricated to contain a large number of semiconductor chips having either or both Bipolar and/or Unipolar (MOS or CMOS) semiconductor devices could have different semiconductor chip size dimensions.
Therefore, after a dicing operation (i.e. such as by using a diamond blade assembly making both X and Y type cutting passes) wherein a semiconductor wafer is diced up into a plurality of semiconductor chips (with either all having the same size dimensions such as, for example, for the production of semiconductor memory chips or differing size dimensions for at least some of the semiconductor chips, it was usually necessary to pick up one or more of these diced semiconductor chips for visual and/or electrical examination purposes and/or for packaging the selected picked-up semiconductor chips in, for example, lead frame type packages.
A major problem with past techniques that were used to pick-up semiconductor chips from a diced semiconductor wafer was the inadvertent destruction of the chip or chips that were being picked up. Initially, semiconductor chips were being handled by, for example, tweezer type devices that would often destroy the semiconductor chip or the semiconductor devices located thereon or one or more electrically conductive lands or pads located on the semiconductor chip surface.
Hence, the semiconductor chip processing or handling technology evolved to a point in thinking about this yield problem where it is deemed to be better, for yield purposes, to remove semiconductor chips from a semiconductor wafer without the use of tweezers or similar type devices operating on or contacting the surface of the semiconductor chips containing the active and/or passive semiconductor devices and/or the metalization pattern for electrical connection to the various (active or passive) semiconductor devices.
In attempting to somehow contact the backside portion of a diced semiconductor chip for the removal thereof from a semiconductor wafer, this backside approach was difficult to do because of a number or problems. One problem was in the difficulty of accurately seeing the precise location of the backside portion of the semiconductor chip to be selected from the usually large number of semiconductor chips that comprise the semiconductor wafer. Another problem was to avoid creating openings in a backing material upon which the diced semiconductor wafer was located because these (undesired) openings in the backing material will prevent passing the combined diced wafer and backing material to pass through other dicing saw machine operations where a vacuum is needed to hold the wafer down, but cannot be achieved if there are holes in the backing material.
Accordingly, a need existed for an apparatus and method for removing semiconductor chips from a diced semiconductor wafer without damaging the active surface of each of the semiconductor chips that are being removed and without creating openings in a backing material located behind the semiconductor wafer.